Engine Tune-Up
DETROIT DIESEL
LIMITING SPEED MECHANICAL GOVERNOR AND INJECTOR RACK
CONTROL ADJUSTMENT
6V-53 ENGINE
The limiting speed mechanical governor is mounted at
2. Back out the buffer screw (Fig. 9) until it extends
the rear of the engine, between the flywheel housing
approximately 5/8" from the lock nut.
and the blower (Fig. 1). The governor is driven by the
right blower rotor drive gear. The left blower rotor
CAUTION: Do not back the buffer screw out
drive gear is driven by a shaft, that passes through the
beyond the limits given, or the control link
governor housing, from the engine gear train. There
lever may disengage the differential lever.
are two types of limiting speed governor assemblies.
The difference in the two governors is in the spring
3. Start the engine and loosen the idle speed adjusting
mechanism (Fig. 7). One has a long spring mecha-
screw lock nut. Then adjust the idle screw (Fig. 8) to
nism, the other has a short spring mechanism.
obtain the desired engine idle speed. Hold the screw
and tighten the lock nut to hold the adjustment.
After adjusting the exhaust valves and timing the fuel
NOTE: The recommended idle speed for non-
injectors, adjust the governor and position the injector
EPA certified engines is 500-600 rpm, but may
rack control levers.
vary with special engine applications.
NOTE: Before proceeding with the governor and
4. Stop the engine, clean and remove the governor
injector rack adjustments, disconnect any
cover and the valve rocker covers. Discard the gaskets.
supplementary governing device. After the
adjustments are completed, re-connect and
5. Start and run the engine, between 800 and 1000
adjust the supplementary governing device.
rpm, by manual operation of the differential lever.
CAUTION: Do not overspeed the engine.
Adjust Governor Gap
6. Check the gap between the low-speed spring cap,
With the engine stopped and at operating tempera-
and the high-speed spring plunger with a .0015" feeler
ture, adjust the governor gap as follows:
gage. If the gap setting is incorrect, reset the gap
1. Remove the high-speed spring retainer cover.
Fig. 1 - Limiting Speed Governor Mounting
Fig. 2 Adjusting Governor Gap
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